1. Field of the Invention
This present invention relates generally to monitoring the temperature of a fluid, e.g., a fluid within a subsea installation for oil or gas extraction or processing. In particular, the invention relates to a temperature sensor that employs a sensing element disposed at an accessible location and is operable to measure a temperature at a remote subsea location.
2. Description of the Related Art
In many applications in the production and processing of oil and gas, it is helpful to monitor the temperature of fluids flowing through a pipe or contained with a vessel. For example, in a subsea fluid extraction well, temperature sensors can be provided at downhole locations and within a subsea tree installed to control production from the well. The temperature sensors may be operable to monitor a temperature of hydrocarbons fluids flowing through the well and subsea tree and also to monitor the temperature of hydraulic fluids or mechanisms for operating various valves, actuators or control devices located on the subsea tree. The temperature readings provided by the sensors can facilitate optimization of production from the well and can be analyzed to predict and prevent equipment failure or dangerous conditions.
The operational life of the temperature sensors could be substantially shorter than the operational life of the fluid extraction well; at least since temperature sensors often employ electronics that are vulnerable to the subsea environment or high temperature. Thus, it may be necessary to replace the temperature sensors during the operational life of the well. In some instances, to permit replacement of the temperature sensors, it may be necessary to suspend operations of the well, which can be expensive and hazardous. For example, in some cases, valves are provided in a fluid conduit to suspend fluid flow through the conduit to isolate a temperature sensor that has failed from the fluid flowing through the conduit. However, since these valves are often left dormant for fifteen years or more while the temperature sensor is operational, these valves themselves can be subject to failure. Additionally, it can be difficult to avoid discharging the fluid into the ambient environment when valves are employed to replace a temperature sensor.
Moreover, the location of the measurement location can make replacement of the temperature sensors challenging. For example, when temperature readings of a fluid at a downhole location are required, replacement of a temperature sensor might require extraction and replacement of lengthy sections of equipment.
Accordingly, recognized is the need for a temperature sensor with a reliable structure that can be readily replaced. Also, recognized is the need for a temperature sensor operable to measure the temperature at a measurement point that is substantially remote from any electronics or other vulnerable components that often require replacement in a subsea environment.